Title: Improved method for replacing PCB-containing coolants in electrical induction apparatuswith substantially PCB-free dielectric coolants
Application Number: 85109359 Application Date: 1985.11.26
Publication Number: 1002570 Publication Date: 1986.08.20
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: B01D11/04;B01D15/00;H01F27/10
Applicant(s) Name: Union Carbide Corporation (US) Old Ridgebury Road, Address:
Inventor(s) Name: Gilbert Richard Atwood
Attorney & Agent: HE GUANYUAN YANG KAI
Abstract:
    Method of replacing a PCB-containing coolant in electrical induction apparatus having a vessel containing said PCB-containing coolant, an electrical winding and porous solid cellulosic electrical insulation immersed in, the replacing method comprising steps of (a) draining the PCB-containing coolant from the vessel, (b) filling the vessel with an interim dielectric coolant, (c) electrically operating the apparatus, (d) removing interim coolant containing eluted PCB, (e) repeating steps (b), (c) and (d) a sufficient number of times until the PCB elution rate does not exceed 5 times a selected target rate, (f) filling the vessel with PCB-free high boiling dielectric silicone oil as coolant, (g) electrically operating the apparatus, (h) repeating steps (f), (g) and (h) a sufficient number of times until the PCB elution rate into the silicone oil is less than the selected target rate, and refilling the vessel with a substantially PCB-free dielectric cooling liquid.
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